[syslinux] Checking if host is on the same subnet

[Alexandre Blanchette]

We are doing a deployment across many sites, we're doing one site at a time
and we're bringing a "mobile server" (a laptop, really) to keep traffic
local instead saturating the WAN link of each site.

I'd like to make a script so each client can determine if the mobile server
is on the same subnet either with a ping with a zero TTL value, with the
ip/netmask and a bit of binary logic, or any other mean.

Currently, PXELINUX is calling an iPXE script, so the solution can be at
either level.

-- 
Alexandre Blanchette <blanalex at gmail.com>